In a process of manufacturing a semiconductor substrate (hereinafter, referred to simply as a “substrate”), conventionally, substrate processing apparatuses have been used for supplying a processing liquid to a substrate being rotated and performing various processings on the substrate. In such a substrate processing apparatus, a cup part is sometimes provided around the substrate to receive a processing liquid and the like spattering from the substrate by centrifugal force.
In an apparatus for processing a semiconductor substrate disclosed in Japanese Patent Application Laid-Open No. 2011-181588 (Document 1), a processing fluid is injected from a nozzle toward an upper surface of a substrate being rotated and unnecessary substances on the substrate are thereby removed. Around the substrate, provided is a spatter guard cover. At an upper portion inside the spatter guard cover, provided is an annular shower header, and with a liquid jetted from the shower header, a liquid film is formed on an inner surface of the spatter guard cover. Since the unnecessary substances removed from the substrate are rinsed out by the liquid film before being deposited on the spatter guard cover, this prevents contamination of the spatter guard cover with the unnecessary substances.
In a coating apparatus disclosed in Japanese Patent Application Laid-Open No. 2009-214052 (Document 2), a resist liquid is supplied onto a center portion of an upper surface of a substrate being rotated and the upper surface of the substrate is thereby coated with the resist liquid. Around the substrate, provided is a cup. Inside the cup, provided is an annular mist supply nozzle, and by spraying a mist from the mist supply nozzle toward an inner surface of the cup, a liquid film is formed on the inner surface of the cup. The mist spattering from the substrate by centrifugal force comes into contact with the liquid film and is thereby adsorbed by the liquid film.
Also in a liquid processing apparatus disclosed in Japanese Patent Application Laid-Open No. 2011-86826 (Document 3), a resist liquid is supplied onto a center portion of an upper surface of a substrate being rotated and the upper surface of the substrate is thereby coated with the resist liquid. Around the substrate, provided is an outer cup. A cleaning solution is discharged while going down along the inner surface of the outer cup, and a liquid film of the cleaning solution is thereby formed on the inner surface of the outer cup. The resist spattering from the substrate by centrifugal force is captured by the liquid film of the cleaning solution.
On the other hand, in a substrate processing apparatus disclosed in Japanese Patent Application Laid-Open No. 2003-45838 (Document 4), a processing liquid is supplied onto a center portion of an upper surface of a substrate being rotated and a processing is thereby performed on the substrate. Around the substrate, provided is a splash guard. Further, when the processing is performed on the substrate, a cutoff plate facing the upper surface of the substrate is disposed at a position in proximity to the upper surface of the substrate. The processing liquid spattering from the substrate is received by the splash guard and the cutoff plate. A mist of the processing liquid caused by collision of the processing liquid against the substrate is deposited on an upper surface of the cutoff plate and the like. Then, when the processing on a predetermined number of substrates is ended, the cutoff plate escapes to an escape position above the substrate and the splash guard, and the cutoff plate is cleaned at the escape position. Cleaning of the upper surface of the cutoff plate is performed by supplying a cleaning solution onto the upper surface of the cutoff plate being rotated at the escape position.
In the substrate processing apparatuses disclosed in the Documents 1 to 3, the processing liquid spattering from the substrate into the surroundings by centrifugal force goes through the liquid film formed on the inner surface of the cup part and collides against the inner surface of the cup part. The droplets caused by the collision of the processing liquid against the liquid film on the inner surface of the cup part may fly inward in a radial direction from the cup part at an angle in accordance with an incident angle of the processing liquid to the liquid film and be deposited onto the substrate.